Basic Information

The Air Quality System (AQS) contains ambient
air pollution data collected by EPA, state, local, and tribal air
pollution control agencies from thousands of monitoring
stations. AQS also contains meteorological data, descriptive
information about each monitoring station (including its geographic
location and its operator), and data quality assurance/quality
control information. The Office of Air Quality Planning and
Standards (OAQPS) and other AQS users rely upon the
system data to assess air quality, assist in
Attainment/Non-Attainment designations, evaluate State
Implementation Plans for Non-Attainment Areas, perform modeling for
permit review analysis, and other air quality management
functions. AQS information is also used to prepare reports for
Congress as mandated by the Clean Air Act.

Today, States, Local and Tribal agencies submit their data
directly to AQS via this web application. Registered
users may also retrieve data through the AQS application and through
the use of third party software such as the Discoverer tool from
Oracle Corporation. Data from AQS is also
available via the AQS Data Mart.

User Support is provided through the EPA Call
Center. The toll free number is 866-411-4EPA.

Timeliness and Accuracy of Data

EPA regulations require state environmental agencies to report
air monitoring data at least quarterly. Data for one calendar
quarter are due to EPA by the end of the following quarter. However,
some values may be absent due to incomplete reporting, and some
values may be subsequently changed due to quality assurance
activities.

If you find an error in AQS, we hope you will let us know so that
we may correct it. You may use the
Contact Us
link or you may contact directly the people responsible for the data. Air
monitoring:
state
environmental agencies